An increasing number of eukaryotic genes are being found to have naturally occurring antisense transcripts. In humans the number of antisense transcripts is estimated to be at least 1,600 and there are several reasons to suggest that the actual number is very much higher. Antisense gene transcripts appear to be associated in one way or another with regulation of expression of their sense transcripts and they have been linked to genetic imprinting and disease. Most of the knowledge of antisense transcripts is derived from in silico analysis of expressed sequence tags and full length transcripts. A method to facilitate direct experimental analysis of antisense would be highly valuable. We propose to develop a method for identification and expression analysis of antisense transcripts in a high throughput manner in the same way as gene expression microarrays are used to study expression of normal (sense) RNA. In fact, our method is designed to identify antisense transcripts with currently available gene expression microarrays. We envision the commercialization of two research products. First a dual RNA amplification kit to identify and study naturally occurring antisense transcripts, and second an improved conventional RNA amplification kit to study sense transcripts which will enable the gene expression analysis of clinical samples from which the RNA is frequently degraded. [unreadable] [unreadable] [unreadable]